Early Sexual Abuse Linked to Later Psychosis

Action Points

Note that this study indicates that child sexual abuse is a risk factor for later development of psychotic disorders, including schizophrenia.

Point out that the study cannot determine causality and is subject to confounding by a number of factors such as social disadvantage.

Children who are sexually abused, particularly if the abuse involves penetration and occurs during early adolescence, are at risk for later developing a psychotic disorder, an Australian case-control study found.

Compared with controls, who had a rate of adult psychosis of 1.4%, the rate among 2,759 children who experienced abuse was 2.8% (OR 2.1, 95% CI 1.4 to 3.1, P<0.001), according to Margaret C. Cutajar, DPsych, of Monash University in Clifton Hill, Victoria, and colleagues.

And for the 1,737 cases where penetration occurred, the rate of subsequent psychosis was 3.4%, the researchers reported in the November Archives of General Psychiatry.

Studies have confirmed that abused children have increased risks for various mental health problems, including depression, anxiety, and substance abuse.

Because the literature also has suggested a possible link with later psychotic disorders, including schizophrenia, Cutajar and colleagues analyzed the subsequent history of all children who had been referred to the police and child protection authorities for sexual abuse in the state of Victoria between 1964 and 1995.

These were compared with 2,677 matched controls taken from local voter registration rolls.

Almost 80% were girls, and the mean age when they were examined for possible abuse was 10.22 years.

Penetration by a finger, penis, or object occurred in 63%, and was more common among girls than boys (64.9% versus 55.2%, P<0.001).

Schizophrenia was diagnosed in 1.9% of the abuse victims compared with 0.7% of controls (OR 2.6, 95% CI 1.6 to 4.4, P<0.001).

Among those who had experienced penetration -- both boys and girls -- the rate of later schizophrenia was 2.4%.

In contrast, sexual abuse not involving penetration was not associated with either later psychosis or schizophrenia.

Compared with controls who developed schizophrenia at a mean age of 30.44 years, the abuse victims were younger when diagnosed, at 27.36 years.

The mean age when the abuse occurred was 12.27 years among those who developed schizophrenia compared with a mean age of 10.18 years in those who didn't become ill (P<0.001), according to the researchers.

Being older than 12 years and experiencing penetration left the victims "particularly vulnerable," the researchers wrote, with 4.1% and 3.2% developing a psychotic disorder or schizophrenia, respectively.

Furthermore, particularly high rates of later illness were seen in the children who had been abused by multiple perpetrators (5.5%, OR 4.05, 95% CI 1.63 to 10.05, P<0.001).

After controlling for age and penetration, abuse by more than one person left victims 2.92 times more likely to be diagnosed with schizophrenia (95% CI 1.13 to 7.34, P<0.05).

Moreover, the combination of penetration in the early teen years increased the chance of later psychosis fourfold, while penetration at 12 years or later plus multiple abusers elevated the risk 15-fold, to higher than 17%.

There are several possible explanations for why rape of young adolescents may heighten their chance of later psychosis, according to the researchers.

For instance, if victims are already in the early prodromal phase of psychiatric illness, they may be less skilled at dealing with predators. Furthermore, they were likely to have reached an important phase of psychosocial development.

"The older victim's ability to understand the nature and implications of the abuse may further compound the trauma," the researchers wrote.

The study had several limitations, according to the researchers. There may have been some loss of later medical history among the abused children, if they moved away or changed their names.

Also, the investigators were unable to exclude possible cases of undetected abuse in the control population.

In addition, cases that come to the attention of authorities may represent a particularly disadvantaged population.

Finally, the analysis couldn't completely establish causality -- just that serious sexual abuse is a risk factor for later psychotic illness.

"Establishing that severe [childhood sexual abuse] is a risk factor for schizophrenia does have important clinical implications irrespective of questions of causality and irrespective of whether those whose abuse is revealed are typical," the researchers observed.

These children should be provided with ongoing support to maximize their functioning and ease their transition to adulthood, "in the knowledge that they are at greater risk of developing a psychotic illness," the researchers noted. They added that under such a scenario, if these children do become ill, treatment can then begin promptly.

The lead author received an Australian postgraduate award scholarship.

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